Finland is heading towards winter at a broadly normal seasonal pace, according to the latest monthly forecast from the European Centre for Medium-Range Weather Forecasts (ECMWF), weather service Foreca reports.
Early to mid-October is typically when autumn brings the fastest cooling in Finland, according to Foreca meteorologist Joanna Rinne.
“As solar radiation decreases, each week is cooler than the one before,” she writes.
The forecast, issued on 11 October and covering the period into early November, suggests weekly average temperatures will remain broadly close to seasonal norms. That still means progressively colder conditions as the season advances, although temperatures can fluctuate within individual weeks.
Signs of winter have already appeared. According to Foreca, the season’s first snow fell in Kainuu and some other parts of central Finland on 9–10 October. The Oustajärvi weather station in Muonio, Finnish Lapland, recorded −13.3°C on Monday, 12 October. Snow or sleet is also possible in northern Lapland on Wednesday, 14 October.
For the week of 12–18 October, Finland is expected to be influenced mainly by southwesterly airflow. Parts of western Finland may receive more rain than usual, while rainfall across much of the country should be typical for the time of year.
During the following week, 19–25 October, the prevailing airflow is expected to turn westerly. Average temperatures and rainfall are forecast to remain close to seasonal norms.
Late-October outlook remains highly uncertain
From the week beginning 26 October, confidence in the forecast drops sharply.
Rinne says the positions and movements of high- and low-pressure systems, together with the distribution of air masses, become too uncertain to draw firm conclusions about departures from normal temperatures or rainfall.
For the week beginning 2 November, there is a tentative signal that relatively mild, wet southwesterly airflow could return. However, Foreca stresses that confidence remains very low.
Long-range forecasts describe weekly or monthly averages, not the weather on individual days. A week that finishes close to the seasonal average can still contain considerable swings between milder and colder conditions.